Johannesburg - The nine-year-old son of a Wits University scientist found the fossil of a new hominid species that lived 1.95 million years ago, the scientist revealed on Thursday.

Speaking at the official unveiling of two partial fossils - that of a child and a woman - found in the Cradle of Humankind, Professor Lee Berger said Matthew found the child's fossil on August 15 2008.

Berger, a paleoanthropologist at the University of the Witwatersrand, undertook a project with Professor Paul Dirks, then head of the university’s School of Geosciences, to map known fossil sites in the Cradle of Humankind Heritage site, to permanently record their location.

“At the beginning of this project there were approximately 130 known cave sites in the region and around 20 fossil deposits,” Berger said at the unveiling of their find.

They soon began finding dozens of previously unidentified fossil sites. One day he took his son and dog Tal for a walk in the area.

He gave Matthew a talk on fossils and said: “Let’s go and find fossils”.

“A minute-and-a-half later he called me and said he had found a fossil. I knew he had found an antelope fossil (which was a usual find), but he was my nine-year-old son, so I had to go and look,” said Berger.

Instead, what Matthew had found was the clavicle (collar bone) of an early hominid child. A few days later he led a group of scientists to the caves. The group failed to find anything, but as they took a break, Berger saw a bone sticking out of a rock.

Teeth

He realised it was the humerus (upper arm bone) of a hominid and went down the pit and saw it was articulated with a scapula (shoulder blade).

As he put his hand against the wall, two hominid teeth fell into his hands.

In the following months, the scientists found what are probably the most complete skeletons of early hominids discovered to date and by far the most complete remains of any hominid.

Paul Dirks said the two hominids were probably looking for water and fell into a 30m deep pit, where they died. Their remains were then probably washed into a deeper cave in the pit, where Berger and his son found them.

The fossil of the female, estimated to have been in her late 20s to early 30s, were found right under the fossil of the child, which was estimated to have been between 11 and 13 years old. Both were about 1.27m tall.

“They may have lived together. They looked into each others eyes. They may have been related and they died at the same time,” said Berger.

The two, which Berger called a new species of human ancestors, was named Australopithecus sediba. Australopithicus means “southern ape”, after the Taung child, while sediba means "natural spring" in Sotho.